DESCRIPTION: Cardiac depression is more pronounced in the neonatal heart than in the adult organ. The studies described in this project are designed to achieve the overall goal of identifying the mechanism underlying age-related (neonate versus adult) differences in the cardiac depressant effects of volatile anesthetics. This proposal addresses two of the three possible factors altering cardiac function: intracellular calcium and the sensitivity of the contractile apparatus to intracellular calcium. Using an adult versus neonatal rat model, the mechanisms underlying the effect of volatile anesthetics on 1) intracellular calcium regulation related specifically to influx through the L-type channel sand calcium release from the sarcoplasmic reticulum, and 2) Ca-sensitivity of force generation will be addressed, with the underlying hypothesis that both factors contribute to cardiodepression secondary to volatile anesthetics.